U.S. patent application number 15/022764 was filed with the patent office on 2016-08-18 for filter group with presence sensor of water in diesel fuel.
This patent application is currently assigned to UFI FILTERS S.P.A.. The applicant listed for this patent is UFI FILTERS S.P.A.. Invention is credited to Giorgio GIRONDI.
Application Number | 20160236123 15/022764 |
Document ID | / |
Family ID | 49519054 |
Filed Date | 2016-08-18 |
United States Patent
Application |
20160236123 |
Kind Code |
A1 |
GIRONDI; Giorgio |
August 18, 2016 |
FILTER GROUP WITH PRESENCE SENSOR OF WATER IN DIESEL FUEL
Abstract
A filter cartridge (40) for filtering a fluid comprising a
tubular filter wall (43) and at least an annular support plate (42)
fixed to a lower end of the filter wall (43) and made of at least
an electrically-insulated material, comprising at least a
conductive strip (50) made of an electrically conductive material,
partially sunk in the support plate (42) and provided with at least
a portion (51, 52) exposed therefrom.
Inventors: |
GIRONDI; Giorgio; (Mantova,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UFI FILTERS S.P.A. |
Porto Mantovano (MN) |
|
IT |
|
|
Assignee: |
UFI FILTERS S.P.A.
Porto Mantovano (MN)
IT
|
Family ID: |
49519054 |
Appl. No.: |
15/022764 |
Filed: |
September 16, 2014 |
PCT Filed: |
September 16, 2014 |
PCT NO: |
PCT/IB2014/001877 |
371 Date: |
March 17, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 29/13 20130101;
B01D 2201/291 20130101; B01D 36/005 20130101; B01D 2201/50
20130101; B01D 36/006 20130101; B01D 35/18 20130101; B01D 35/005
20130101 |
International
Class: |
B01D 36/00 20060101
B01D036/00; B01D 29/13 20060101 B01D029/13; B01D 35/00 20060101
B01D035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2013 |
IT |
RE2013A000066 |
Claims
1. A filter cartridge (40), for filtering a fluid, comprising a
tubular filter wall (43) and at least an annular support plate (42)
fixed to a lower end of the filter wall (43) and made of at least
an electrically-insulated material, wherein it comprises at least a
conductive strip (50) made of an electrically conductive material,
partially sunk in the support plate (42) and provided with at least
a portion (51, 52) exposed therefrom, wherein the conductive strip
(50) comprises a first exposed portion (51) and a second exposed
portion (52) and at least a tract (53) of the conductive strip (50)
that is intermediate between the first and the second exposed
portion (51, 52) and is sunk in the support plate (42).
2. The cartridge (40) of claim 1, it wherein the cartridge (40)
comprises at least a pair of the conductive strips (50).
3. The cartridge of claim 2, wherein the conductive strips (50) of
the pair of conductive strips (50) are electrically insulated from
one another.
4. The cartridge (40) of claim 2, wherein the conductive strips
(50) of the pair of conductive strips (50) are electrically
connected to one another by means of at least a resistor (55) at
least partially sunk into the support plate (42).
5. The cartridge (40) of claim 1, wherein the first exposed portion
(51) is located at a distance from the axis of the support plate
(42) that is smaller with respect to the distance from the axis of
the support plate (42) of the second exposed portion (52).
6. The cartridge (40) of claim 1, wherein the conductive strip (50)
exhibits at least a tract (53) with a longitudinal axis
substantially arranged in a radial direction sunk into the support
plate (42).
7. The cartridge (40) of claim 1, wherein the first exposed portion
(51) is located at a greater axial height with respect to the
second exposed portion (52).
8. The cartridge (40) of claim 7, wherein the first exposed portion
(51) is located at a higher level than the lower support plate
(42), radially aligned to at least a portion of the filter wall
(43), and the second exposed portion (52) is located at a lower
level than and/or a same level as a lower axial end of the lower
support plate (42).
9. The cartridge (40) of claim 7, wherein the conductive strip (50)
exhibits at least the tract (53) having the longitudinal axis
substantially arranged in an axial direction sunk in the support
plate (42).
10. The cartridge (40) of claim 1, wherein the support plate (42)
comprises at least a hollow shank (421) coaxial with the filter
wall (43) and communicating with the internal volume of the filter
wall (43) by means of a central hole (420) of the support plate
(42), a first exposed portion (51) of the conductive strip (50)
being located internally of the hollow shank (421) and a second
exposed portion (52) being located externally of the hollow shank
(421).
11. The cartridge (40) of claim 10, further comprising an annular
seal (424) associated to the hollow shank (421).
12. A filter group (10) comprising an external casing (20) provided
with at least an inlet (23) of the fluid to be filtered, at least
an outlet (24) of the filtered fluid, and a filter cartridge (40),
according to claim 1, contained internally of the casing (20), such
that the filter wall (43) is crossed by the fluid flowing from the
inlet (23) towards the outlet (24) and the support plate (42) of
the filter cartridge (40) is the lower plate proximal to the bottom
of the casing (20), at least an electrical contact (33) of a sensor
of the water in the diesel (30) arranged in proximity of the bottom
of the casing (20) and associated thereto, wherein the at least an
exposed portion (51) of the conductive strip (50) is able to come
into contact with the at least an electrical contact (33), when the
filter cartridge (40) is contained internally of the casing (20) so
as to prolong the electrical contact (33).
Description
TECHNICAL FIELD
[0001] The present invention relates to a filter group and the
relative filter cartridge for filtration of diesel fuel in the
automotive field.
[0002] In greater detail, the invention relates to a filter group
provided with a sensor of the presence of water in diesel fuel and
the relative filter cartridge.
PRIOR ART
[0003] As is known, the filtering of the diesel fuel in the
automotive field is generally obtained with a filter group
comprising an external casing provided with a substantially
beaker-shaped body, the open end of which is closed by a cover.
[0004] At least one from between the cover and the beaker body is
provided with an inlet for the diesel to be filtered and an outlet
of the filtered diesel. At least a filter cartridge is contained
internally of the casing, which filter cartridge is for
sub-dividing the internal volume of the casing into two distinct
chambers, of which a first chamber communicating with the inlet and
a second chamber communicating with the outlet. In this way, the
diesel flowing from the inlet towards the outlet of the filter
group is forced to cross the filter cartridge, which retains the
impurities that might be present therein.
[0005] A certain quantity of water is also present in the diesel,
which due to the greater specific weight thereof with respect to
the specific weight of the fuel to be treated (for example diesel
oil) tends to accumulate on the bottom of the beaker body and must
therefore be eliminated during the functioning of the filter
group.
[0006] In the prior art, for facilitating the separation of the
water from the fuel, filter walls are generally used which are able
to separate the water by coalescence from the fuel and/or
hydrophobic nets which keep the water separated from the fuel, so
that the water collects by force of gravity on the bottom of the
casing.
[0007] Further, also known is the use of discharge conduits
associated to the casing of the filter group which place the lower
part of the casing, where the water tends to collect, in
communication with discharge means and/or aspirating means of the
water, so that the accumulated water is constantly emptied from the
casing.
[0008] To detect the presence of accumulated water in the casing,
with the aim of preventing the level of water from exceeding a
predetermined maximum level and so that it can therefore be
accessed and sent into the combustion chamber, there are sensors
present (known as water in fuel sensors) which are associated to
the casing in such a way that a sensitive part of the sensor is
located in proximity of the bottom thereof.
[0009] The sensors detecting the presence of water are operatively
connected to the electronic board of the vehicle and are configured
so as to generate an alarm signal in a case where the water reaches
the maximum level, which generally corresponds to the level at
which the sensitive part of the sensor is located internally of the
casing.
[0010] When the alarm signal is generated it is sufficient to empty
the water present on the bottom of the casing via the discharge
conduit.
[0011] The water presence sensors in practice comprise an electric
circuit that terminates with one or more uncovered electrodes,
which are the sensitive part of the sensor and are destined to be
arranged internally of the casing and immersed in the fluid being
filtered.
[0012] The level the water has reached in the casing is calculated
from the measurement of the conductivity of the liquid about the
electrodes, which is different if the electrodes are immersed in
the diesel or in water.
[0013] There exist water presence sensors the electrodes of which
are fixed to the bottom of the casing or which are fixed to the
lower end of the longitudinal stem which branches from the upper
cover of the casing.
[0014] A drawback encountered in the filter groups of known type,
in which the water presence sensor is integrated in the casing, is
the fact that a non-original filter cartridge or a cartridge
arranged wrongly internally of the casing might obscure the sensor
or render it inefficient.
[0015] Further, the water presence sensors of known type are either
only in the chamber of the casing positioned upstream of the filter
wall containing the diesel to be filtered or in only the chamber of
the casing positioned downstream of the filter wall containing the
filtered diesel.
[0016] Lastly, a drawback encountered in known filter groups
relates to the fact that the water level sensor is located at a
height independently of the filter cartridge, and might therefore
be located at a greater height with respect to the level of the
lower support plate of the filter cartridge and therefore at a
level corresponding to a sector of the filter wall.
[0017] An aim of the present invention is to obviate the
above-mentioned drawbacks in the prior art, with a solution that is
simple, rational and relatively inexpensive.
[0018] The above aims are attained by the characteristics of the
invention reported in the independent claim. The dependent claims
delineate preferred and/or particularly advantageous aspects of the
invention.
DESCRIPTION OF THE INVENTION
[0019] In particular the invention discloses a filter cartridge for
filtering a fluid comprising a filter wall having a tubular shape
and at least an annular support plate fixed to a lower end of the
filter wall and made of at least an electrically-insulating
material.
[0020] In the invention, the filter cartridge comprises at least a
conductive strip made of an electrically conductive material,
partially sunk in the support plate and provided with at least a
portion exposed therefrom.
[0021] For example, the exposed portion is destined to come into
contact with an exposed electrical contact sunk in the fluid being
filtered of a water level sensor.
[0022] With this solution the position of the water level sensor
internally of the filter group can be freed from the maximum level
permitted of the water accumulating on the bottom of the
casing.
[0023] Further, thanks to this solution the conductive strip can be
configured in such a way that it prolongs the level sensor of the
water immersed in the fluid being filtered, so that the exposed
portion of the conductive strip, which is for certain located at a
lower level with respect to all the filter wall, is able to detect
when a level of the water in the casing of the filter group has
reached a level that is surely lower than the whole filter wall,
preventing direct contact between the water and the filter
wall.
[0024] Further, in an advantageous aspect of the invention, the
filter cartridge comprises at least a pair of conductive strips,
for example separated from one another.
[0025] In a first embodiment of the invention, the conductive
strips of the pair of conductive strips are advantageously
electrically insulated from one another.
[0026] With this solution, the conductive strips are destined to be
a simple prolongation internally of the casing of the exposed
electrical contacts of the water level sensor.
[0027] Alternatively, the conductive strips of the pair of
conductive strips can be electrically connected to one another by
means of at least a resistor at least partially sunk into the
support plate.
[0028] With this solution, the structure of the water level sensor
can be simplified, making a diagnostic check thereof possible by
means of the electrical resistance offered by the resistor
integrated in the filter cartridge.
[0029] Further, thanks to the solution using the water level sensor
it is possible to determine the presence of the correct filter
cartridge (i.e. the filter cartridge originally intended for the
filter group), as well as the correct positioning thereof, in the
filter group, for example, making use of non-original replacement
items more difficult.
[0030] In both above-described variants, in a further advantageous
aspect of the invention each conductive strip can comprise at least
two exposed portions, of which at least a first exposed portion
(destined to come into contact with an exposed electrical contact
immersed in the fluid being filtered of the water level sensor) and
at least a second exposed portion (distal from the first exposed
portion), wherein the first exposed portion is located at a
distance from the axis of the support plate that is smaller with
respect to the distance from the axis of the support plate of the
second exposed portion, at least a tract of the intermediate
conductive strip between the first and the second exposed portion
being (totally) sunk into the support plate.
[0031] In this way, two zones can be defined, for example two
separate chambers of the casing, in which the conductive strip
enters into contact (by means of the respective exposed portions)
with the fluid being filtered, with the aim of being able to
determine a reaching of the critical level of the water in the
casing, independently in one or the other zone.
[0032] In a further aspect of the invention the conductive strip
can exhibit at least a tract, for example the intermediate tract
between the exposed portions, if the exposed portions are two or
more, with a longitudinal axis substantially arranged in a radial
direction sunk into the support plate.
[0033] In a second embodiment of the filter cartridge, each
conductive strip can comprise at least two exposed portions, of
which a first exposed portion and a second exposed portion.
[0034] The first exposed portion is, for example, located at a
greater axial height than the second exposed portion, and at least
a portion of the conductive strip, intermediate between the first
and the second exposed portion, is sunk in the support plate.
[0035] With this solution, each conductive strip defines an axial
prolongation of an electrical contact.
[0036] The first exposed portion can advantageously be located at a
higher level than the lower support plate, i.e. radially aligned
with at least a portion (lower) of the filter wall, and the second
exposed portion is located at a lower level than and/or a same
level as a lower axis end of the lower support plate.
[0037] Further, at least the portion (intermediate) with the
longitudinal axis of the conductive strip can substantially be
arranged in an axial direction and be sunk in the support
plate.
[0038] In a still further aspect of the invention, the support
plate comprises at least a hollow shank coaxial with the filter
wall and communicating with the internal volume of the filter wall
by means of a central hole of the annular support plate, a first
exposed portion of the conductive strip being located internally of
the hollow shank and a second exposed portion being located
externally of the hollow shank.
[0039] For example, the filter cartridge comprises an annular seal
associated to the hollow shank.
[0040] Thanks to this solution the presence of water can be
detected in two separate environments (and communicating only
through the filter wall) of the casing in which the filter
cartridge is located, one internally of the filter wall and the
other external thereof, for example one containing filtered diesel
and the other containing diesel to be filtered.
[0041] A further aspect of the invention relates to a filter group
comprising an external casing provided with at least an inlet of
the fluid to be filtered, at least an outlet of the filtered fluid
and a filter cartridge, as described above, contained internally of
the casing, such that the filter wall is crossed by the fluid
flowing from the inlet towards the outlet and the support plate of
the filter cartridge is the lower plate proximal to the bottom of
the casing, at least an electrical contact of a water sensor in the
diesel being arranged in proximity of the bottom of the casing and
associated thereto.
[0042] In the invention, the at least an exposed portion of the
conductive strip is able to come into contact with the at least an
electrical contact, when the filter cartridge is contained
internally of the casing so as to prolong (for example axially
and/or radially) the electrical contact internally of the external
casing. With this configuration of the filter cartridge and the
filter group, the above-detailed advantages can be attained.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Further characteristics and advantages of the invention will
emerge from a reading of the following description provided by way
of non-limiting example, with the aid of the figures illustrated in
the appended tables.
[0044] FIG. 1 is a front view of a filter group according to the
invention.
[0045] FIG. 2 is a section view along section line II-II of FIG.
1.
[0046] FIG. 3 is a view from below of a filter cartridge according
to the invention.
[0047] FIG. 4 is a front view of FIG. 3.
[0048] FIG. 5 is the section view along section line V-V of FIG.
6.
[0049] FIG. 6 is the section view along section line VI-VI of FIG.
4.
[0050] FIG. 7 is a view from below of a lower support plate of the
filter cartridge of FIG. 3.
[0051] FIG. 8 is a view from above of FIG. 7.
[0052] FIG. 9 is a section view along section line IX-IX of FIG.
10.
[0053] FIG. 10 is a section view along section line X-X of FIG.
11.
[0054] FIG. 11 is a front view of FIG. 7.
[0055] FIG. 12 is detail XII of FIG. 2, with the water discharge
conduit in a closed configuration.
[0056] FIG. 13 is a detail of FIG. 13, with the water discharge
conduit in a closed configuration.
[0057] FIG. 14 is a longitudinal section view of a second
embodiment of a filter group according to the invention.
BEST WAY OF CARRYING OUT THE INVENTION
[0058] In the figures, reference numeral 10 denotes in its entirety
a filter assembly for filtration of diesel fuel in a diesel engine
of a motor vehicle. The filter assembly 10 comprises an outer
casing, generally denoted by 20, which includes, for example, a
beaker-shaped body 21, and a cover 22 suitable for closing the
beaker-shaped body 21.
[0059] The cover 22 comprises an inlet conduit 23 for the diesel to
be filtered and an outlet conduit 24 for the filtered diesel.
[0060] The beaker-shaped body 21 comprises, for example positioned
at the bottom thereof, a discharge conduit 25 for the water that
accumulates on the bottom of the beaker-shaped body 21, provided
with a connecting cap 26 which will be better described in the
following.
[0061] In the illustrated example (see FIG. 2 and FIGS. 12 and 13),
the discharge conduit 25 has a substantially cylindrical internal
portion 250, coaxial with the beaker-shaped body 21 and rising from
the bottom of the beaker-shaped body 21 for a limited axial
portion.
[0062] The internal portion 250 is internally hollow and is
substantially beaker-shaped with the concavity thereof facing on
the opposite side with respect to the beaker-shaped body 21.
[0063] The internal portion 250 exhibits for example an internal
thread for the screwing-in of the connecting cap 26.
[0064] The internal portion 250 comprises, at the top wall thereof
(the bottom of the beaker-shaped body), a first through-hole 251,
which--normally occluded by the connecting cap 26--enables
discharge of the water contained in the casing 20, as will become
apparent in the following, when it is released from the connecting
cap 26.
[0065] Alternatively, a discharge conduit can be also provided on
the cover 22 and be connected to a cannula drawing from the bottom
of the beaker-shaped body 21.
[0066] The filter assembly 10 includes a water level sensor 30,
which for example comprises a plate-shaped head 31 (for example,
disc-shaped) from which a stem inferiorly extends 32, which stem
internally supports an electronic circuit and which bears at a
lower end thereof at least an exposed electrical contact 33.
[0067] The example shows two electrical contacts 33 which, for
example, are located diametrically opposite.
[0068] One only electrical contact 33 might be provided, or more
than two electrical contacts 33, depending on the operation of the
electronic circuit.
[0069] Each electrical contact 33 is made from a conductive metal
plate that can be housed in a flattening 34 made in the stem
32.
[0070] The water level sensor 30 is configured to detect the level
of water that accumulates on the bottom of the beaker-shaped body
21 during filtration of diesel fuel and is associated, as known to
a technical expert of the sector, to an electronic control unit
(not shown) of the vehicle.
[0071] In the illustrated example the water level sensor 30 is
fixed to the cover 22, for example so that the plate-shaped head 31
is arranged externally of the casing 20 and the rod 32 projects
inside the casing itself, for example through a special hole made
in the cover 22.
[0072] In practice, the stem 32 can be substantially coaxial with
the casing 20.
[0073] Further, each electrical contact 33 can be arranged in the
housing 20 near the bottom of the beaker-shaped body 21 and at a
distance therefrom.
[0074] A heater element 34 (such as an electric heater) can be
housed, for example, inside the plate-shaped head 31, suitable for
heating the diesel contained in the casing 20, for example during
the first moments of engine operation.
[0075] However, the water level sensor might alternatively branch
from the bottom of the beaker-shaped body 21.
[0076] A filter cartridge, denoted in its entirety by 40, is
accommodated internally of the casing 20; the filter cartridge 40
includes for example an upper support plate 41 and a lower support
42 plate, which are fixed to opposite ends of a tubular filter wall
43, in the illustrated example a pleated wall, which defines and
delimits a substantially cylindrical internal volume.
[0077] The filter wall 43, alternatively, could be a depth
wall.
[0078] The upper support plate 41 is substantially disc-shaped and
has a central hole 410 centred on the longitudinal axis A of the
filter wall 43.
[0079] The lower support plate 42 is also substantially disc-shaped
and has a central hole 420 centred on the longitudinal axis A of
the filter wall 43.
[0080] The lower support plate 42 is in particular made of at least
an electrically insulating material, such as a plastic
material.
[0081] The central holes 410 and 420 of the upper support plate 41
and the lower support plate 42 are threaded on the portion
projecting internally of the beaker-shaped body 21 of the stem
32.
[0082] In particular, the central hole 410 of the upper support
plate 41 inserts on an terminal internal portion of the outlet
conduit 24, which is able to accommodate the upper portion of the
stem 32 with radial play.
[0083] A seal ring 411 is interposed between the internal end
portion of the outlet conduit 24 and the internal edge of the
central hole 410 of the upper support plate 31, which seal ring 411
is fixed to the internal edge of the central hole 410, such that
the internal volume of the filter cartridge 40 communicates
exclusively with the outlet conduit 24.
[0084] Furthermore, the free end of the stem 32 protrudes below the
upper support plate 41 and terminates internally of the internal
volume of the filter wall 43.
[0085] The lower end of the rod 32 enters, with radial play, in the
central hole 420 of the lower support plate 420 and terminates
substantially at the same level (slightly lower) as the lower
support plate.
[0086] Further, the filter cartridge 40 includes a hollow support
core 45 arranged coaxially and internally of the filter wall 43,
which core 45 affords radial openings and is fixed at opposite ends
thereof respectively to the upper support plate 41 and the lower
support plate 42.
[0087] With the above-described configuration, the filter cartridge
40 sub-divides the internal volume of the casing 20 into a first
chamber 211, defined externally of the filter wall 43 and
internally of the casing 20, which communicates with the inlet
conduit 23 of the diesel to be filtered, and into a second chamber
212, coinciding with the internal volume of the filter wall 43,
which communicates with the outlet conduit 24 of the filtered
diesel.
[0088] The filter cartridge 40 further comprises a hydrophobic net
46, for example also of tubular shape, coaxially inserted in the
filter wall 43 so as to intercept the flow of fuel through the
filter wall itself.
[0089] Alternatively or in addition, the filter wall 43 is of a
coalescent type in order to improve the separation of water from
the diesel fuel.
[0090] The filter assembly 10 comprises orientation means of the
filter cartridge 40, suitable for orientating the filter cartridge
40 within the housing 20.
[0091] The orientation means comprise at least a pair of
positioning grooves 412, afforded in at least one of the upper
support plate 41 and the lower support plate 42, in the example the
upper support plate 41, at an external edge thereof and placed in a
predetermined reciprocal angular position, in the example
diametrically opposite.
[0092] The orientation means further comprise a pair of ribs 220,
fashioned internally of at least one between the cover 22 and the
beaker-shaped body 21, in the example the cover 22, which, being
placed at the same reciprocal angular position of the pair of
positioning grooves 412, are configured to engage the pair of
positioning grooves 412, when the filter cartridge 40 is correctly
arranged in the casing 20.
[0093] In practice, the filter cartridge 40 can be arranged in only
a few possible orientations (two in the example) inside the housing
20.
[0094] The lower support plate 42 comprises a hollow shank 421
coaxial with the filter wall 43 and arranged on the opposite side
of it.
[0095] The hollow shank 421 is able to axially extend the internal
volume of the filter wall 43 by a limited axial length.
[0096] The hollow shank 421, for example, is substantially
truncoconical with an upper end 422 (the broad end) branching
downwards from the lower support plate 42 and with the lower end
423 (the tapered end) free.
[0097] The hollow shank 42 can also exhibit a different shape, for
example substantially cylindrical.
[0098] The lower end 423 of the hollow shank 421 comprises an
annular seal 424 able to surround (frontally, internally and/or
externally) the edge of the second end.
[0099] The hollow shank 421 is able to insert substantially snugly
and sealedly (by means of the annular seal 424) on the internal
portion 250 of the discharge conduit 25.
[0100] Further, the bottom of the beaker-shaped body 21 and the
hollow shank 421 comprise coupling means, such as elastic teeth and
respective seatings, able to define a mutual coupling, for example
of the snap type, bayonet type or a combination of the two.
[0101] In practice, the hollow shank 421 (with the top wall of the
internal portion 250) defines a collecting volume 425 of the water
communicating with the internal volume of the filter wall 43 via
the central hole 420 of the lower support plate 42.
[0102] The second chamber 212 (of the filtered diesel) is defined
by the internal volume of the filter wall 43 and by the collecting
volume 425 inside the hollow shank 421 of the lower support plate
42.
[0103] The hollow shank 421 comprises one or more radial internal
ribs 426 developing along the whole axis.
[0104] In the illustrated example there are four internal ribs 426
equally spaced and having a triangular/trapezoidal shape, but they
might also be a different number, for example two.
[0105] For the purposes of the present invention, the filter
cartridge 40 includes at least a conductive strip 50 made of
electrically conductive material, which is partially incorporated
in the lower support plate 42.
[0106] The conductive strip 50 comprises at least an exposed
portion 51,52 of the lower support plate 42, for example, the
conductive strip 50 exhibits at least a surface which emerges or
projects from the lower support plate 42, in which the metal
exposed portion 51 is accessible from the inside and/or outside of
the lower support plate 42 so as to define an exposed electrical
contact.
[0107] The at least an exposed portion 51,52 of the conductive
strip 50 is destined to come into contact with the at least an
electrical contact 33 of the water level sensor 30 when the filter
cartridge 40 is correctly inserted in the casing 20, electrically
extending the electronic circuit of the water level sensor 30.
[0108] The conductor strip 50 includes a first exposed portion 51
that extends internally of the central cavity of the lower support
plate 42, for example internally of the cylindrical shank 421 (or
the central hole 420).
[0109] The first exposed portion 51 therefore includes an end
portion of the conductive strip 50 which projectingly branches
internally of the central cavity of the lower support plate 42; a
portion 53 of the conductive strip 50 is located within the body of
the lower support plate 42, sunk therein, for example by
co-moulding of the metal conductor strip 50 with the plastic lower
support plate 42 or, alternatively, forcibly inserted in a seating
formed in the plastic lower support plate.
[0110] The first exposed portion 51 is arranged substantially in a
radial direction and can exhibit a curved portion (for example
downward) so as to axially extend the electrical contact of the
electrical circuit of the water level sensor.
[0111] In any case, the position of the first exposed portion 51
(the lowest part of it within the casing 20) can define the maximum
level reachable by the water in the casing 20 at which the water
level sensor 30 is configured to signal a necessary emptying of the
filter assembly.
[0112] In the example the first exposed portion 51 is arranged
internally of the collecting volume 425, i.e. internally of the
hollow shank 421, for example in proximity of the upper end 422
thereof.
[0113] It is however possible for the first exposed portion 51 to
be positioned substantially at the level of the central hole 420 of
the lower support plate 42.
[0114] In a first variant of the invention there can be the use of
a single conductive strip 50 as described above, in a case where
the water level sensor 30 exhibits a single electrical contact
33.
[0115] The case illustrated in the figures shows a second variant
of the invention in which the filter cartridge 40 comprises two
conductive strips 50 separated from one another, though they can
also be in a number of greater than two if necessary.
[0116] The two conductive strips 50, for example, are symmetrical
with respect to an axial vertical plane.
[0117] The first exposed portions 51 are, for example, arranged
diametrically opposite, so as to come into contact, in use, each
with a respective electrical contact 33 of the water level sensor
(in a case in which they are two in number and also diametrically
opposite).
[0118] It is advantageously possible for each conductive strip 50
to exhibit a second exposed portion 52, which is located at a
distance from the axis of the lower support plate greater than the
distance from the axis of the casing 20 (and therefore of the plate
of the lower support 42) with respect to the first exposed portion
51.
[0119] In this case the portion 53 of the conductive strip 50
incorporated in the lower support plate 42, is an intermediate
portion between the first and the second exposed portions 51,52
which places the two exposed portions in electrical connection.
[0120] The second exposed portion 52 is for example an end portion
of the conductive strip 50.
[0121] The second exposed portion 52 is arranged substantially
externally of the hollow shank 421 and protrudes radially, by a
limited radial amount therefrom.
[0122] In the illustrated example, the second exposed portion 52
exhibits an upper surface substantially resting on the lower
surface of the lower support plate 42, and is located at the
conjoining zone between the lower support plate 42 and the hollow
shank 421.
[0123] Alternatively, the second exposed portion 52 can have a
downwards-curved and axially-projecting portion, for example
resting on the outside of the hollow shank 421.
[0124] The second exposed portion 52 might be arranged in a more
peripheral area of the lower support plate 42 depending on
requirements.
[0125] In any case, the position of the second exposed portion 52
(the lowest part of it internally of the casing 20) can define the
maximum level reached by the water in the casing 20 in which the
water level sensor 30 is configured to signal the need to empty the
filter assembly 10.
[0126] The second exposed portion 52 is, in the example, arranged
internally of the first chamber 211 (diesel to be filtered), or
externally of the hollow shank 421 and the filter wall 43, for
example in proximity of the upper end 422 of the hollow shank
421.
[0127] The portion 53 of each conductive strip 50, for example, is
sunk in the hollow shank 421, for example with radial longitudinal
development.
[0128] In the illustrated example the portion 53 is positioned at
one of the internal ribs 426.
[0129] The other internal ribs 426 not affected by the portion 53
are able to maintain the lower end of the stem 32 of the water
level sensor 30 in position.
[0130] In this case too, a first variant of the invention might
include the use of a single conductive strip 50 as described above
(i.e. with two exposed portions 51,52), in a case where the water
level sensor 30 exhibits a single electrical contact 33.
[0131] The illustrated example shows two conductive strips 50
placed diametrically opposite one another, each provided with a
first exposed portion 51, a second exposed portion 52 and an
intermediate portion 53, as described above.
[0132] Further, in the case where there are two conductive strips
50 (whether they have a single exposed portion 51 or two exposed
portions 51,52), they can be electrically insulated from each other
and each function as an extension of the electrical contact 33 or
in the collecting volume 425 in the first chamber or 211 or in both
chambers.
[0133] In an advantageous embodiment, illustrated in the figures,
the two conductive strips 50 (whether they have only one exposed
portion 51 or two exposed portions 51,52) are mutually electrically
connected by a resistor 55, which is for example sunk (totally or
at least partially) in the lower support plate 42 (e.g. in the
hollow shank 421, or in the plate).
[0134] In the example the resistor 55 is configured so as to
provide an electrical difference that is in fact different to both
the electrical resistance of the water and the electrical
resistance of the diesel fuel.
[0135] The resistor 55, for example, comprises a plate, for example
made of metal and semi-annular, arranged coaxially with respect to
the lower support plate 42 and having a diameter comprised between
the inner diameter and the outer diameter of the lower support
plate 42.
[0136] The resistor 55 is for example at least partially sunk in
the body of the lower support plate 42, for example by co-moulding
therewith.
[0137] The resistor 55 exhibits the opposite ends thereof
respectively in contact with a portion of a conductive strip 50,
for example with the portion 53 thereof which is also sunk in the
lower support plate 42 (or with the second exposed portion 52).
[0138] The connecting cap 26, which could also be protected
independently of what is described above, is configured to occlude
both the first through-hole 251 of the internal portion 250 of the
outlet conduit 25, and a second through-hole 252 made on the bottom
of the beaker-shaped body 21, for example in the conjoining area
between the internal portion 250 and the bottom of the
beaker-shaped body.
[0139] In particular, (as shown in the larger-scale details of
FIGS. 12 and 13), the bottom of the beaker-shaped body 21 comprises
one or more second through-holes 252 made in the respective lowered
regions of the bottom, arranged about the internal portion 250 and
proximal thereto.
[0140] In practice, the first through hole 251 is able to place the
collection volume 245 (defined internally of the hollow shank 421
and above the top wall of the internal portion 250) in
communication with outside the casing 20; each second through-hole
252 is able to place the first chamber 211 in communication with
the external casing 20.
[0141] The connecting cap 26 comprises a broadened head 261 from
which a threaded stem 262 rises.
[0142] The threaded stem 262 can be screwed to the internal thread
of the internal portion 250, while the broadened head 261 can be
received substantially snugly in a recessed seating of the external
wall of the bottom of the beaker-shaped body 21 aligned in plan
view with the second through-holes 252.
[0143] The threaded stem 262 supports a first end seal 263 (annular
or disc-shaped) placed at the free end of the threaded rod and
compressible between the top wall of the internal portion 250 and
the threaded stem to occlude (substantially sealingly) the first
through-hole 251 (from outside the casing 20).
[0144] The threaded stem 262 can further comprise a tapered end
insertable substantially snugly internally of the first
through-hole 251.
[0145] The broadened head 261 comprises a second front seal 264
(annular) placed at the base of the threaded rod 262, which is
compressible between the bottom wall of the external beaker-shaped
body 21 and the upper surface (annular) of the broadened head 261,
so as to occlude (substantially sealingly) each second through-hole
252 (from outside the casing 20).
[0146] The second front gasket 264 further comprises a radial lip
protruding able to ensure the radial seal between the broadened
head 261 and the side walls of the recessed seating formed on the
bottom of the beaker-shaped body 21.
[0147] The broadened head 261 is conformed so as to be able to be
screwed and unscrewed from a usual instrumentation.
[0148] The connecting cap 26 also comprises at least one water
drainage channel 265 defined internally of at least one from
between the broadened head 261 and the threaded stem 262.
[0149] In practice, the drain 265 exhibits at least an axial
portion which flows inferiorly externally of the bottom of the
broadened head 261, which is connectable to a usual water drain
pipe.
[0150] The axial portion of the drainage channel 265 extends along
the threaded stem 262 and terminates with one or more radial
portions open at the outer skirt of the threaded rod 262, for
example through radial openings or axial grooves which are placed
at a higher level than the level of the second front seal 264.
[0151] In practice, following a partial unscrewing of the
connecting cap 26 (see FIG. 13), the drainage channel 265 is able
to place the collecting volume 425 in communication with the
exterior of the casing 21 by means of, in sequence: the first
through hole 251, the radial section and the axial portion of the
drainage channel and is also suitable for placing the first chamber
211 in communication with the outside of the casing 21 by means of,
in sequence: each second through-hole 252, the radial section and
the axial portion of the drainage channel.
[0152] Each through-hole 252 is not occluded by the filter
cartridge 40, as it is arranged at a respective recessed region of
the bottom of the beaker-shaped body 21.
[0153] FIG. 14 illustrates in its entirety a second embodiment of
the filter group 10 for filtering diesel oil in a Diesel engine of
a motor vehicle.
[0154] The filter group 10 comprises an external casing 20, which
in turn comprises, for example, a beaker body 21, and a cover 22
able to close the beaker body 21.
[0155] The cover 22 (and/or the beaker body 21) comprises an inlet
conduit (not illustrated, as entirely identical to the conduit
illustrated for the first embodiment) for the diesel to be filtered
and an outlet conduit (also not illustrated for the same reasons as
those above) from which the filtered diesel exits.
[0156] The beaker body 21 can comprise, for example located at the
bottom, a discharge conduit (not illustrated as identical to the
conduit illustrated for the first embodiment) for the water which
accumulates on the bottom of the beaker body 21, provided with a
connecting cap for example as described above. Alternatively, a
simple drainage cap screwed to the bottom of the beaker can be
included.
[0157] Alternatively, a discharge conduit might also be included on
the cover 22 and be connected to a cannula sourcing from the bottom
of the beaker body 21.
[0158] The filter group 10 comprises a water level sensor 30, which
for example comprises a plate-shaped head 31 (for example
disc-shaped) from which a stem 32 inferiorly projects, which stem
32 internally supports an electronic circuit and at a lower end of
bears an exposed electrical contact 33.
[0159] In the example, two electrical contacts 33 are shown which,
for example, are located diametrically opposite one another.
[0160] One electrical contact 33 alone or more than two electrical
contacts 33 can be included, according to the functioning of the
electronic circuit.
[0161] Each electrical contact 33 is realized by a conductive metal
plate that can be housed in a flattened part realized in the stem
32.
[0162] The water level sensor 30 is configured such as to detect
the water level that accumulates on the bottom of the beaker body
21 during the filtration of the diesel and is associated, as known
to the technical expert in the sector, to an electronic control
board (not illustrated) of the vehicle.
[0163] The water level sensor 30 is fixed in the example to the
cover 22, for example so that the plate-shaped head 31 is arranged
externally of the casing 20 and the stem 32 projects internally of
the casing, for example by means of a special through-hole 220
realised in the cover 22, for example with an interposing of a seal
ring 221.
[0164] In practice, the stem 32 is able to be arranged
substantially coaxially to the casing 20.
[0165] Further, each electrical contact 33 can be arranged in the
casing 20 in proximity of the bottom of the beaker body 21 and at a
distance therefrom.
[0166] For example, a heating element (such as an electric heater,
not illustrated) can be housed internally of the plate-shaped head
31 for heating the diesel contained in the casing 20, for example
in the first instants of functioning of the engine.
[0167] A filter cartridge, denoted in its entirety by reference
numeral 40, is housed internally of the casing 20, which filter
cartridge 40 comprises, for example, an upper support plate 41 and
a lower support plate 42, which are fixed to opposite ends of a
tubular filter wall 43, in the illustrated example a pleated wall,
which defines and delimits a substantially-cylindrical internal
volume.
[0168] The filter wall 43 alternatively might be a depth wall.
[0169] The upper support plate 41 is substantially plate-shaped and
annular (or disc-shaped with an axial through-hole) and exhibits a
central hole 410 (through-hole) centred on the longitudinal axis A
of the filter wall 43.
[0170] The central hole 410 of the upper support plate 41 can be
axially prolonged upwards by a central shank rising from the upper
support plate 41.
[0171] The central hole 410 of the upper support plate 41 is
inserted on a shank projecting internally of the external casing 20
of the cover 22 so that the upper support plate 41 (and the filter
cartridge 40) can be axially retained (for example by means of
hooks of known type).
[0172] In particular, the central hole 410 of the upper support
plate 41 inserts on the projecting shank by interposing of a seal
ring 411 fixed to the external edge of the central shank, so that
the internal volume of the filter cartridge 40 can communicate for
example with the inlet conduit opening into the volume comprised
internally of the projecting shank.
[0173] The lower support plate 42 is also substantially in a closed
disc shape, for example without axially-passing holes.
[0174] The lower support plate 42 is in particular made of at least
an electrically-insulating material, such as for example a plastic
material.
[0175] Further, the free lower end of the stem 32 projects below
the upper support plate 41 and terminates internally of the
internal volume of the filter wall 43, for example at a higher
level than the lower support plate 42.
[0176] The filter cartridge 40 can further comprise a support core
(not illustrated) that is hollow and located coaxially and
internally of the filter wall 43, which support core is provided
with radial openings and is fixed at opposite ends respectively to
the upper support plate 41 and the lower support plate 42.
[0177] The filter cartridge 40, as occurred in the first embodiment
illustrated in FIGS. 1-13, defines an internal volume (located
internally of the filter wall 43 and axially delimited by the upper
and lower support plates 41, 42) and an opposite external
volume.
[0178] Owing to the above-described configuration, the filter
cartridge 40 sub-divides the internal volume of the casing 20 into
a first chamber 211, defined externally of the filter wall 43 and
internally of the casing 20, which communicates with the outlet
conduit of the diesel to be filtered and into a second chamber 212,
coinciding with the internal volume of the filter wall 43, which
communicates with the inlet conduit of the diesel to be
filtered.
[0179] Alternatively the first chamber 211 can communicate with the
inlet conduit of the diesel to be filtered and the second chamber
212 communicates with the outlet conduit of the filtered diesel
according to constructional needs.
[0180] The filter cartridge 40 can further comprise a hydrophobic
net (not illustrated), for example also tubular, coaxially inserted
in the filter wall 43, in such a way as to intercept the flow of
fuel which crosses the filter wall.
[0181] The lower support plate 42 might include draining holes, for
example located axially aligned with a toroidal region of
interspace comprised (internally) between the filter wall 43 and
the hydrophobic net (for example tubular and coaxially inserted
internally of the filter wall 43 and supported at opposite ends
thereof by the upper support plate 41 and the lower support plate
42).
[0182] In this configuration of the filter cartridge 40 the
hydrophobic net can sub-divide the internal volume of the filter
wall 43 into two environments of which one of the environments is
in communication with the bottom of the beaker body 21 via the
drainage holes, in which the water accumulates on separation from
the diesel (by means of the hydrophobic net).
[0183] Alternatively or additionally, the filter wall 43 is of a
coalescent type in such a way as to improve the separation of the
water from the diesel.
[0184] The filter group 10 can comprise orientating means of the
filter cartridge 40, able to orientate the filter cartridge 40
internally of the casing 20.
[0185] The orientating means can be entirely alike to those
described for the first embodiment described above and the
description is not repeated here for the sake of brevity.
[0186] In practice, thanks to the orientating means, only a limited
number of orientations of the filter cartridge 40 are allowed (for
example two) internally of the casing 20.
[0187] For the aims of the present invention, the filter cartridge
40 comprises at least a conductive strip 50 made of an
electrically-conductive material, which is partially sunk in the
lower support plate 42.
[0188] The conductive strip 50 comprises at least an exposed
portion 51, 52 from the lower support plate 42, for example the
conductive strip exhibits at least a surface emerging or projecting
from the lower support plate 42, in which the exposed metal portion
51 is accessible from inside and/or from outside the lower support
plate 42 such as to define an exposed electrical contact.
[0189] The at least an exposed portion 51, 52 of the conductive
strip 50 can come into contact with the at least an electrical
contact 33 of the water level sensor 30 when the filter cartridge
40 is correctly inserted in the casing 20, electrically prolonging
the electronic circuit of the water level sensor 30.
[0190] The conductive strip 50 comprises a first exposed portion 51
which axially projects internally of the internal volume of the
filter cartridge 40.
[0191] In practice, the first exposed portion 51 is located at a
higher level than the lower support plate 42.
[0192] The first exposed portion 51 further comprises an end
portion of the conductive strip 50 which branches projectingly
above the lower support plate 42 internally of the internal volume
of the filter cartridge 40 (i.e. internally of the second chamber
212 into which the internal volume of the casing 20 is sub-divided
by the filter cartridge 40).
[0193] A further portion 53 of the conductive strip 50 is located
internally of the body of the lower support plate 42 and sunk
therein, for example by means of co-moulding of the metal
conductive strip 50 with the plastic lower support plate 42 or,
alternatively, by forced insertion in a seating realized in the
plastic lower support plate 42.
[0194] The first exposed portion 51 is arranged with the
longitudinal axis arranged substantially in an axial direction (in
such a way as to axially prolong the electrical contact of the
electrical circuit of the water level sensor) in an offset position
with respect to the lower support plate 42 and can exhibit a curved
portion (for example towards the central axis of the lower support
plate 42). The first exposed portion 51 (in particular the free end
or a zone proximal thereto) can come into contact (for example
forced) with the at least an electrical contact 33 of the water
level sensor 30 when the filter cartridge 40 is correctly inserted
in the casing 20, in such a way that the conductive strip 50 can
electrically prolong (in an axial direction) the electronic circuit
of the water level sensor 30.
[0195] A first variant embodiment of the invention might include
use of a single conductive strip 50 as described in the foregoing,
in a case in which the water level sensor 30 exhibits a single
electrical contract 33.
[0196] In the illustrated embodiment in the figure, a second
variant of the invention is shown, in which the filter cartridge 40
comprises two conductive strips 50, separated from one another, but
can also be in a number of more than two if required.
[0197] The two conductive strips 50 for example are symmetrical
with respect to an axial vertical plane.
[0198] The first exposed portions are, for example, arranged
diametrically opposite, so as to come into contact, in use, each
with a respective electrical contact 33 of the water level sensor
(in a case in which the water level sensors are also two in number
and diametrically opposite).
[0199] It is advantageously possible for each conductive strip 50
exhibits a second exposed portion, which is located at a lower
level with respect to the first exposed portion 51 and in
particular at a lower level the (or the same level as) the lower
axial end of the lower support plate 42.
[0200] In this case the portion 53 of the conductive strip 50, sunk
into the lower support plate 42, is an intermediate portion (with a
substantially axial development) between the first and the second
exposed portion 51, 52 which place the two exposed portions in
electrical connection.
[0201] The second exposed portion 52, for example, comprises or is
an end portion of the conductive strip 50.
[0202] The second exposed portion 52 projects axially, for a
limited axial tract, below the lower support plate 42, so as to be
contained in the volume external of the filter cartridge 40, i.e.
in the first chamber 211 into which the internal volume of the
external casing 20 is sub-divided by the filter cartridge 40.
[0203] In the illustrated example, the second exposed portion 52
exhibits a longitudinal axis substantially axially arranged (and
offset) and projects inferiorly of the lower support plate 42.
[0204] In any case, the position of the second exposed portion 52
(of the lowest part thereof internally of the casing 20) can define
the maximum level reachable by the water in the casing 20 to which
the water level sensor 30 is configured so as to signal the
necessary emptying of the filter group 10.
[0205] The second exposed portion 52 is, in the example, arranged
internally of the first chamber 211 (of the filtered diesel).
[0206] In practice, as happened for the first embodiment
illustrated in FIGS. 1-13, the first exposed portion 51 is located
internally of the internal volume delimited by the filter cartridge
40 and the second exposed portion 52 is located externally of the
internal volume thereof (i.e. in the external volume of the filter
cartridge 40).
[0207] Further, in a case in which two conductive strips 50 are
present (whether they have one portion only exposed 51 or two
portions exposed 51, 52), the strips can be electrically insulated
from one another and each function as extensions of the electrical
contact 33 in the first chamber 211 (or in any case below the lower
support plate 42).
[0208] In an advantageous embodiment variant, shown in the figures,
the two conductive strips 50 (whether they have a single exposed
portion 51 or two exposed portions 51, 52) are electrically
connected to one another by a resistor 55, which is for example
sunk (totally or at least partially) in the lower support plate
42.
[0209] In the example the resistor 55 is configured so as to
provide a different electrical difference both from the electrical
resistance of the water and from the electrical resistance of the
diesel.
[0210] The resistor 55, for example, comprises a plate-shaped
element or a filament, for example made of metal, for example
semi-annular or straight or of a different shape which electrically
connects the two conductive strips 50.
[0211] The resistor 55 is for example at least partly (or totally)
sunk into the body of the lower support plate 42, for example by
co-moulding therewith.
[0212] The resistor 55 exhibits the opposite ends respectively in
contact with a portion of a conductive strip 50, for example with
the further portion 53 thereof also sunk into the lower support
plate 42 (or with the first or second exposed position 51, 52
according to requirements).
[0213] In the light of the above, the operation of the filter group
10 (according to the first embodiment illustrated in FIGS. 1-13) is
as follows.
[0214] To make the filter group 10 operative, the connecting cap 26
is used to occlude firstly the first and the second through-holes
251, 252.
[0215] Then the filter cartridge 40 is inserted axially into the
beaker-shaped body 21 in such a way that the hollow shank 421
inserts on the internal portion 250 of the discharge conduit
25.
[0216] It then proceeds, closing the cover 22 on the beaker-shaped
body 21.
[0217] The cover 22 is rotated with respect to the longitudinal
axis A of the filter cartridge 40 until the ribs 220 insert in the
positioning grooves 412.
[0218] Once the positioning grooves 412 are engaged by the ribs
220, the correct mutual positioning between the filter cartridge 40
and the cover 22 is ensured, so as to ensure direct contact between
an exposed portion (the first exposed portion 51) of one or both
the conductive strips 50 and a respective electrical contact 33 of
the water level sensor 30.
[0219] The functioning of the water level sensor 30 is different
depending on the level sensor used and/or the configuration
thereof.
[0220] The following contains a description of some operating
methods of the water level sensor 30 in combination with the filter
cartridge 40 in the filter group 10.
[0221] If the water level sensor 30 exhibits a single electrical
contact 33 and the filter cartridge 40 a single conductive strip 50
the operation of the water level sensor 30 is as follows.
[0222] The water level sensor 30 always comprises a pair of
electrical contacts, of which only one, the electrical contact 33,
is immersed in the fluid under filtration and the other is
grounded.
[0223] Since water has a higher electrical conductivity than diesel
oil, if the conductive strip 50 is fully immersed in the diesel,
once the electronic circuit is powered-up, the strip 50 measures a
first value of current intensity at the heads of the electrical
contacts, dependent on the electrical resistance of the diesel
fuel.
[0224] If the water that accumulates on the bottom of the housing
20 reaches a level such as to intercept, even only partially, an
exposed portion 51,52 of the conductive strip 50, the electronic
circuit measures, at the heads of the electrical contracts, a
second intensity value of the current, dependent on the electrical
resistance of the water and, therefore, greater than the first
value of current intensity, and signals correspondingly to the
control unit the need to proceed to the emptying of the water
through the discharge conduit 25.
[0225] This happens both in the case in which the conductive strip
50 comprises a single exposed portion 51 and when it comprises the
first exposed portion 51 and the second exposed portion 52, which
are accessible independently of the level of the water present in
the respective environment into which the bottom of the casing 20
is sub-divided.
[0226] If the water level sensor 30 has two electrical contacts 33,
as in the illustrated case, and the filter cartridge 40 comprises
two respective conductive strips 50, the operation of the water
level sensor 30 could be the following.
[0227] Both the electrical contacts 33 are immersed in the fluid
under filtration, as are also the conductive strips 50.
[0228] Since water has a higher electrical conductivity than
diesel, if both of the conductive strips 50 are immersed in the
diesel oil, the electronic circuit, when powered-up, measures a
first value of current intensity at the heads of the electrical
contacts 33 that depends on the electrical resistance of the
diesel.
[0229] If the water accumulating on the bottom of the housing 20
reaches a level such as to contact, even only partially, an exposed
portion 51,52 of the conductive strips 50, the electronic circuit
measures a second current intensity value at the heads of the
electrical contacts 33, dependent on the electrical resistance of
the water and, therefore, greater than the first current intensity
value, and signals correspondingly to the control unit the need to
proceed to the evacuation of the water through the discharge
conduit 25.
[0230] In this case too, this happens both in the case in which the
conductive strips 50 comprise a single exposed portion 51 and when
they comprise the first exposed portion 51 and the second exposed
portion 52, which are accessible independently of the level of the
water present in the respective environments into which the bottom
of the housing 20 is sub-divided.
[0231] Lastly, in a case where the filter cartridge 40 also
includes the resistor 55, it places the two conductive strips 50 in
connection via an electrical resistance that is different from both
the electrical resistance of the water and the electrical
resistance of the diesel (for example greater than the electrical
resistance of the water).
[0232] Therefore, in, a case where the casing is empty (or full of
diesel oil), the electronic circuit once powered-up measures a
reference value of the current intensity at the heads of the
electrical contacts 33, dependent on the electrical resistance of
the resistor 55 (or also of the diesel).
[0233] The electronic circuit and the control unit are configured
such as to generate an alarm signal if the intensity value detected
is different from the reference value, as this might be a sign for
example that the filter cartridge 40 inserted is not the one
originally intended for the determined filter group or is
positioned incorrectly in the casing.
[0234] In any case, if both of the conductive strips 50 are
immersed in the diesel, the electronic circuit when powered-up
measures a first value of current intensity at the heads of the
electrical contacts 33, dependent on the electrical resistance of
the diesel and the resistor 55.
[0235] If the water that accumulates on the bottom of the housing
20 reaches a level such as to involve, even only partially, an
exposed portion 51,52 of the conductive strips 50, the electronic
circuit measures a second intensity value current at the heads of
the electrical contacts 33, dependent on the electrical resistance
of the water and, therefore, greater than the first value of
current intensity, and signals correspondingly to the control unit
the need to proceed to the evacuation of the water through the
discharge conduit 25.
[0236] In the light of the above description, the functioning of
the filter group 10 (according to the second embodiment shown in
FIG. 14) is the following.
[0237] Once the correct reciprocal position between the filter
cartridge 40 and the cover 22 has been ensured, so as to guarantee
direct contact between an exposed position (the first exposed
portion 51) of one or both the conductive strips 50 and a relative
electrical contact 33 of the water level sensor 30, the filter
group 10 is correctly installed.
[0238] The functioning of the water level sensor 30 is different
according to the level sensor used and/or the configuration
thereof.
[0239] Should the water level sensor 30 exhibit a single electrical
contact 33 and the filter cartridge 40 a single conductive strip
50, the functioning of the water level sensor 30 might be the
following.
[0240] The water level sensor 30 still comprises a pair of
electrical contacts, of which one only, the electrical contact 33,
is immersed in the fluid being filtered and the other is
earthed.
[0241] As water has a greater conductivity than diesel, if the
conductive strip 50 is completely immersed in the diesel, once the
electric circuit is activated, the circuit measures a first
intensity value of the current at the heads of the electrical
contacts, which first intensity depends on the electrical
resistance of the diesel.
[0242] If the water accumulating on the bottom of the casing 20
reaches a level such as to intercept, even only partially, an
exposed portion 51,52 of the conductive strip (in particular the
second exposed portion 52 located at a lower level internally of
the external casing 20), the electronic circuit measures, at the
heads of the electrical contacts, a second current intensity value,
depending on the electrical resistance of the water and, therefore,
greater than the first current intensity value, and signals
correspondingly to the electronic control board the need to proceed
to the evacuating of the water via the discharge conduit.
[0243] If the water level sensor 30 exhibits two electrical
contacts 33, as in the illustrated case, and the filter cartridge
40 comprises two respective conductive strips 50, the functioning
of the water level sensor 30 might be the following.
[0244] Both the electrical contacts 33 are immersed in the fluid
being filtered, as are the conductive strips 50.
[0245] As the water has a greater conductivity than the diesel, if
both the conductive strips 50 are immersed in the diesel, once the
electronic circuit is powered-up it measures, at the heads of the
electrical contacts 33, a first current intensity value, depending
on the electrical resistance of the diesel.
[0246] If the water accumulating on the bottom of the casing 20
reaches a level so as to involve, even partially, an exposed
portion 51, 52 of the conductive strips 50 (in particular the
second exposed position 52 located at a lower level internally of
the casing 20), the electronic circuit measures, at the heads of
the electrical contacts 33, a second current intensity, depending
on the electrical resistance of the water and therefore greater
than the first current intensity value, and correspondingly signals
to the electronic control board the need to proceed to the emptying
of the water through the discharge conduit.
[0247] Lastly, in a case in which the filter cartridge 40 also
comprises the resistor 55, it places the two conductive strips in
communication via a different electrical resistance from both the
electrical resistance of the water and the electrical resistance of
the diesel (for example greater than the electrical resistance of
the water).
[0248] Therefore, in a case in which the casing is empty (or in any
case full of diesel), once the electronic circuit is powered up, it
measures, at the heads of the electrical contacts 33, a reference
value of the current intensity, depending on the electrical
resistance of the resistor 55 (or also the diesel).
[0249] The electronic circuit and the control board are configured
in such a way as to generate an alarm signal if the intensity value
detected is different to the reference value, which is for example
an indication that the filter cartridge 40 fitted is not the
original cartridge intended for the determined filter group or is
positioned wrongly in the casing.
[0250] In any case, if both the conductive strips 50 are immersed
in the diesel, once the electronic circuit is powered-up it
measures a first current intensity value at the heads of the
electrical contacts 33, depending on the electrical resistance of
the diesel and the resistor 55.
[0251] If the water that accumulates on the bottom of the casing 20
reaches a level such as to involve, even only partially, an exposed
portion 51, 52 of the conductive strips 50 (in particular the
second exposed portion 52 located at a lower level than the inside
of the external casing 20), the electronic circuit measures, at the
heads of the electrical contacts 33, a second current intensity
value, depending on the electrical resistance of the water and,
therefore, greater than the first current intensity value, and
correspondingly signals to the control board the need to proceed to
the evacuation of the water via the discharge conduit.
[0252] The invention thus conceived is susceptible to numerous
modifications and variations, all within the inventive concept.
[0253] Moreover, all the details are replaceable by other
technically equivalent elements.
[0254] In practice, the materials employed, as well as the
contingent shapes and dimensions, may be any according to
requirements without thereby abandoning the scope of protection of
the following claims.
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